Heat-dissipating tube for electrical apparatus casings and metfod for forming such tubes



C aw Oct. 15, 1929. RICE 1,731,867 HEAT DISSIPATING TUBE FOR ELECTRICAL APPARATUS CASINGS AND METHOD FOR FORMING SUCH TUBES Filed Feb. 17. 1928 Inventor: Kenneth Afiice,

Patented Oct. 15,1929

UNITED STATES HEAT-DISSIPATING TUBE FOR PATENT OFFICE PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRICAL APPARATUS CASINGS AND METFOD FOR FORMING SUCH TUBES Application filed February 17, 1928. Serial No. 255,174.

My invention relates to heat dissipating tubes for oil immersed electrical apparatus casings and to an improved method for producing such tubes. Electrical apparatus produces heat while in operation and this heat must be dissipated to prevent overheating of the apparatus. An electrical device such as a transformer 'is often enclosed in a casing containing an insulating and cooling liquid, the casing being provided with outside tubes through which the liquid may circulate and from which much of the heat absorbed by the their ends toward the casing wall to meet openings in the wall where welded or otherwise sealed joints prevent leakage- The curved ends of the tubes have been provided by bending the tubes or by securing separate elbows to straight vertical sections of tubing either by welding or by threaded joints. The general object of the present invention is to provide an improved heat dissipating tube of this general character, an improved method for forming such a tube and an improved flange connection between the tube and an electrical apparatus casing.

The invention and its advantages will be.

better understood from the following descrip tion taken in connection with the accompanying drawing in which Fig. 1 shows a sectional view of one side of an encased oil immersed transformer provided with a heat dissipating tube formed in accordance with the invention and Figs. 2 to 5 inclusive show one end of a tube duringdiflerent stages of its formation.

Like reference characters indicate similar parts in the different figures of the drawing.

The transformer 10 shown in 1 is immersed in a body of insulating and cooling liquid 11 Within a casing 12. A heat dissipating tube 13has lateral openings at its upper and lower ends which communicate with the interior of the casing 12. Any desired numbei of such tubes may be connected to the casing, of course, to give the desired area of heat dissipating surface. Heat appearing in the transformer 10 is absorbed by the liquid 11 which rises by convection, passes into the upper ends of the tubes 13, descends through these tubes where the heat is dissipated to the surrounding air and finally returns into the lower part of the casing 10 ready to absorb more heat and repeat the cycle;

' The tube 13 is formed from a simple open ended length of tubing such as is indicated in Fig. 2. In many cases, a flattened tube such as is shown will be desirable as it has the advantage of a large heat dissipating surface and a series of openings near the bottom, one

top and one bottom opening for each tube 13 that is to'be attached to the casing. Both ends of each tube are formed in like manner so that a description of one end of a tube and the process of forming it as indicated in Figs. 2 to 5 inclusive will explain the invention clearly. A lateral opening 14 is formed near the end of the tube, the edge of the metal surrounding the opening being bent outwardly to form a flange 15 integral with the tube and surrounding the opening. A similar lateral opening surrounded by an integral outwardly bent flange 15 is also formed near the other end of the tube, the spacing of the two openings along the tube being equal to that of the upper and lower openings in the casing wall to which the tube is to be connected. The tube is long enough to extend slightly beyond the lateral opening at each end.

The ends of the tube beyond the lateral openings 14 are closed and sealed. This may side of the tube as shown in Fi 4. This closed end 16 of the tube may then be trimmed oil to leave only a slightly projecting curved edge 17 shown in Fig. 5 which is welded to form a leak proof seam of attractive curved contour.

The tube 13 is connected to the apparatus casing 12 by placing it against the side wall of the casing with the outwardly bent flanges l5 registering with and preferably slightly entering the upper and lower Wall openings which have been formed to communicate with the tube. The flanges 15 of the tube and the edges of the wall openings are then welded together to secure the tube in place and to prevent leakage. When flattened tubes such as have been described are used, the lateral openings let are preferably formed in one of the longitudinal edges of the tube so that the tube may be connected to the casing 12 with its longer diameter normal to the casing wall.

The invention provides a heat dissipating tube of attractive appearance and which may beformed in a single integral unit including the connections to the apparatus casing. A large amount ofeflective heat radiating surface is exposed to the surrounding air and the tubes connected to the casing may be very close to it so as to take up a minimum amount of space.

The invention has been explained by describing and illustrating a specific form of heat dissipatingtube and a method of producing it but it will be apparent that certain changes may be made Without departing from the scope of the invention as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is 1. A'heat dissipating metal tube for edgewise connection to the wall of an electrical apparatus casing, said tube having spaced elongated openings in one edge thereof and close to its opposite ends, the metal edges surrounding sa1d openings being bent outwardly to form short integral flanges for connection close to its opposite ends, the metal edges surrounding said openings bein bent outwardly to orm short integral fl anges, said flanges being welded to the edges of top and bottom openings in said casing, and the ends of said tube bemg closed by seals close to the outer ends of said openings.

4. A. method of producing a flattened heat dissipating metal tube for an electrical a paratus casing, said method including t e forming of spaced elongated openings in one edge of a flattened tube and close to its opposite ends, bending the metal edges surrounding said openings outwardly to form short integral flanges tor connection to said casing, and sealing the ends of said tube close to the outer ends of said openings.

5. A method of providing an electrical apparatus casing with a flattened heat dissipating metal tube, said method including forming of spaced elongated openings in one edge of a flattened tube and close to its opposite ends, bending the metal edges surrounding said 0 enings outwardly to form short integral anges, sealing the ends of said tube close to the outer ends of said openings, and

welding said flanges to the edges of openings.

in said casing.

In testimony whereof, I have hereunto set my hand this 15th day of Feb. 1928.

KENNETH A. RICE.

to said casing, and the ends of said tube being closed by seals close to the outer ends of said openings.

2. A heat dissipating metal tube for edgewise connection to the wall of an electrical apparatus casing, said tube having spaced elongated openings in one edge thereof and close to its opposite ends, the metal edges surrounding said openings being bent outwardly to form short integral flanges for connection to said casing, and the ends of said tube being closed by seals extending from points close to the outer ends of said openings to points in the opposite edge of the tube nearer its center.

3. The combination with an electrical apparatus casing having openings near the top and bottom of its side wall, of a flattened heat dissipating tube, said tube having spaced elongated openings in one edge thereof and 

